Gender-specific neuroanatomical basis of behavioral inhibition/approach systems (BIS/BAS) in a large sample of young adults: A voxel-based morphometric investigation

Brain gray matter volume of reward-related structures in Inuit adolescents pre- and postnatally exposed to lead, mercury and polychlorinated biphenyls

This study aimed to assess associations between prenatal and postnatal exposure to lead (Pb), mercury (Hg) and polychlorinated biphenyls (PCBs) and gray matter volume of key regions of the brain reward circuit, namely the caudate nucleus, putamen, nucleus accumbens (nAcc), the amygdala, the orbitofrontal cortex (OFC) and the anterior cingulate cortex (ACC). Structural magnetic resonance imaging (MRI) was conducted in 77 Inuit adolescents (mean age = 18.39) from Nunavik, Canada, who also completed the Brief Sensation Seeking Scale (BSSS-4) and Sensation Seeking - 2 (SS-2), two self-report questionnaires evaluating the tendency toward sensation seeking, which is a proxy of reward-related behaviors. Exposures to Pb, Hg and PCBs were measured in cord blood at birth, in blood samples at 11 years old and at time of testing (18 years old). Multivariate linear regressions were corrected for multiple comparisons and adjusted for potential confounders, such as participants' sociodemographic characteristics and nutrient fish intake. Results showed that higher cord blood Pb levels predicted smaller gray matter volume in the bilateral nAcc, caudate nucleus, amygdala and OFC as well as in left ACC. A moderating effect of sex was identified, indicating that the Pb-related reduction in volume in the nAcc and caudate nucleus was more pronounced in female. Higher blood Hg levels at age 11 predicted smaller right amygdala independently of sex. No significant associations were found between blood PCBs levels at all three times of exposure. This study provides scientific support for the detrimental effects of prenatal Pb and childhood Hg blood concentrations on gray matter volume in key reward-related brain structures.

Sex modulated the relationship between trait approach motivation and decision-making

It has been observed that one's Behavioral Approach System (BAS) can have an effect on decision-making under uncertainty, although the results have been mixed. To discern the underlying neural substrates, we hypothesize that sex may explain the conflicting results. To test this idea, a large sample of participants was studied using resting state fMRI, utilizing fractional Amplitude of Low Frequency Fluctuations (fALFF) and Resting-State Functional Connectivity (rsFC) techniques. The results of the Iowa Gambling Task (IGT) revealed an interaction between sex and BAS, particularly in the last 60 trials (decision-making under risk). Males with high BAS showed poorer performance than those with low BAS. fALFF analysis showed a significant interaction between BAS group and sex in the left superior occipital gyrus, as well as the functional connectivity between this region and the left ventrolateral prefrontal cortex. Additionally, this functional connectivity was further positively correlated with male performance in the IGT, particularly in the decision-making under risk stage. Furthermore, it was found that the functional connectivity between left ventrolateral prefrontal cortex and left superior occipital gyrus could mediate the relationship between BAS and decision-making in males, particularly in the decision-making under risk stage. These results suggest possible sex-based differences in decision-making, providing an explanation for the inconsistent results found in prior research. Since the research was carried out exclusively with Chinese university students, it is essential to conduct further studies to investigate whether the findings can be generalized.

Romantic Love and Behavioral Activation System Sensitivity to a Loved One

Research investigating the mechanisms that contribute to romantic love is in its infancy. The behavioral activation system is one biopsychological system that has been demonstrated to play a role in several motivational outcomes. This study was the first to investigate romantic love and the behavioral activation system. In study 1, the Behavioral Activation System-Sensitivity to a Loved One (BAS-SLO) Scale was validated in a sample of 1556 partnered young adults experiencing romantic love. In study 2, hierarchical linear regression was used to identify BAS-SLO Scale associations with the intensity of romantic love in a subsample of 812 partnered young adults experiencing romantic love for two years or less. The BAS-SLO Scale explained 8.89% of the variance in the intensity of romantic love. Subject to further validation and testing, the BAS-SLO Scale may be useful in future neuroimaging and psychological studies. The findings are considered in terms of the mechanisms and evolutionary history of romantic love.

EEG frontal lobe asymmetry as a function of sex, depression severity, and depression subtype

To investigate possible contributors to the inconsistent association between frontal lobe asymmetry (FLA) and depression, EEG data were collected across five frontal sites, and examined for their associations with four subtypes of depression (Depressed mood, Anhedonia, Cognitive depression, Somatic depression). One hundred community volunteers (54 males, 46 females) aged at least 18 yr completed standardized scales for depression and anxiety, and gave EEG data under Eyes Open and Eyes Closed conditions. Results indicated that, although there was no significant correlation between the differences in EEG power across each of the five pairs of frontal sites and total depression scores, there were several meaningful correlations (accounting for at least 10% of the variance) between specific EEG site differences data and each of the four depression subtypes. There were also different patterns of association between FLA and the depression subtypes according to sex, and total depression severity. These findings help to explain the apparent inconsistency in previous FLA-depression results, and argue for a more nuanced approach to this hypothesis.

Biological embedding of early trauma: the role of higher prefrontal synaptic strength

Background: Early trauma predicts poor psychological and physical health. Glutamatergic synaptic processes offer one avenue for understanding this relationship, given glutamate's abundance and involvement in reward and stress sensitivity, emotion, and learning. Trauma-induced glutamatergic excitotoxicity may alter neuroplasticity and approach/avoidance tendencies, increasing risk for psychiatric disorders. Studies examine upstream or downstream effects instead of glutamatergic synaptic processes in vivo, limiting understanding of how trauma affects the brain.Objective: In a pilot study using a previously published data set, we examine associations between early trauma and a proposed measure of synaptic strength in vivo in one of the largest human samples to undergo Carbon-13 (13C MRS) magnetic resonance spectroscopy. Participants were 18 healthy controls and 16 patients with PTSD (male and female).Method: Energy per cycle (EPC), which represents the ratio of neuronal oxidative energy production to glutamate neurotransmitter cycling, was generated as a putative measure of glutamatergic synaptic strength.Results: Results revealed that early trauma was positively correlated with EPC in individuals with PTSD, but not in healthy controls. Increased synaptic strength was associated with reduced behavioural inhibition, and EPC showed stronger associations between reward responsivity and early trauma for those with higher EPC.Conclusion: In the largest known human sample to undergo 13C MRS, we show that early trauma is positively correlated with EPC, a direct measure of synaptic strength. Our study findings have implications for pharmacological treatments thought to impact synaptic plasticity, such as ketamine and psilocybin.

Effects of fun-seeking and external locus of control on smoking behaviour: a cross-sectional analysis on a cohort of working men in Singapore

OBJECTIVES

We examined the combined effects of behavioural inhibition and behavioural activation, on one hand, and locus of control, on the other hand, on different categories of smoking behaviour (non-smoking, ex-smoking, occasional smoking, daily smoking).

DESIGN

This study adopted a cross-sectional design. Participants completed questionnaires regarding demographics, smoking patterns, behavioural inhibition/behavioural activation systems and locus of control.

SETTING

The study was conducted across four companies from the transportation, cooling plant and education sectors in Singapore.

PARTICIPANTS

Three hundred sixty-nine male working adults were included in the final sample.

RESULTS

Corroborating previous research, a logistic regression model examining behavioural inhibition/behavioural activation systems revealed that the fun-seeking aspect of behavioural activation was a unique predictor in distinguishing non-smokers from daily smokers (OR=1.24, p=0.012). By contrast, in a separate model examining locus of control, external locus of control was found to be a unique predictor in distinguishing non-smokers from daily smokers (OR=1.13, p<0.001). In addition, a third model combining both behavioural inhibition/behavioural activation systems and locus of control found that only external locus of control remained a significant predictor (OR=1.12, p<0.001). Further analyses revealed a mediating effect of external locus of control on the relationship between fun-seeking and smoking behaviour. That is, the increase in the odds of daily smoking due to fun-seeking was explained by external locus of control (direct pathway OR=1.20, p=0.058; indirect pathway OR=1.04, p<0.050).

CONCLUSIONS

Overall, fun-seeking through its influence on external locus of control indirectly affects daily smoking behaviour, suggesting a more complex relationship than shown in previous research.

The Role of Sensitivity to Reward and Punishment in Aggression

The study of the risk and protective factors in aggression is of fundamental importance for our society. The aim of this research was to clarify the role of sensitivity to reward/punishment in aggression and provide a better understanding of the mechanisms underlying this relationship, particularly given that previous studies in the literature have yielded mixed results. To this end, two studies were conducted. In Study 1 (484 participants; M_age = 39.09; 48.6s women), we explored the relationship between sensitivity to reward and punishment and four components of aggression: physical, verbal, anger, and hostility. In Study 2 (229 participants; M_age = 21.52; 56.77% women), we investigated the moderating role of emotion regulation ability in this relationship. The findings of Studies 1 and 2 supported the existence of a positive relationship between sensitivity to reward and aggression, that is, a high reactivity to reward acted as a risk factor. With respect to sensitivity to punishment, mediation analysis revealed that this variable may act both as a protective factor as well as a risk factor for behavioral aggression. A higher reactivity to punishment had a direct negative effect on physical and verbal aggression, inhibiting aggressive behavior. However, a higher reactivity to punishment also implied a positive indirect effect on physical and verbal aggression through an increase in anger and hostility. Interestingly, Study 2 revealed that these indirect effects were moderated by emotion regulation ability. Our results could help to inform the design of aggression prevention and intervention programs for reducing the impact of this behavior on our society.

Temperamental Change in Adolescence and Its Predictive Role on Anxious Symptomatology

Growing evidence supports the hypothesis that temperamental traits are not static throughout adolescence. The known links between both reactive and regulatory temperament and anxiety symptoms should be investigated bearing this hypothesis in mind. This study collected self-reported data on behavioral inhibition system (BIS) sensitivity, attentional control (AC), and anxiety symptomatology, from 296 adolescents (64.2% girls; M = 12.96 years at the first assessment, SD = 0.47) every six months, four times over eighteen months. The relationships between temperament factors (AC and BIS sensitivity), considered longitudinally (by means of their trajectories) and anxiety symptoms were investigated using Multigroup Latent Growth Modeling (MLGM), as well as the mediating effect of sex on trajectories and anxiety. BIS sensitivity decreased over time and showed differential patterns across sexes. AC remained relatively stable and we found no sex influence on its trajectory. On the other hand, we observed that the BIS sensitivity trajectory was a significant predictor of anxiety symptomatology at age 15. In conclusion, temperamental changes between the ages of 13 and 15 seem to play a relevant role in explaining subsequent anxiety symptomatology, under the mediating influence of sex.

Gray matter volumetric correlates of dimensional impulsivity traits in children: Sex differences and heritability

Previous research investigated the cerebral volumetric correlates of impulsivity largely in moderate-sized samples and few have examined the distinct correlates of dimensions of impulsivity, sex differences, or heritability of the correlates. Here, we performed voxel-based morphometry analysis of data (n = 11,474; 5,452 girls, 9-10 years) curated from the Adolescent Brain Cognition Development project. In a linear regression with all five UPPS-P subscores as regressors and age in months, total intracranial volume, study site, and scanner model as covariates, higher levels of lack of premeditation, and sensation seeking were correlated with larger cortical and subcortical gray matter volumes (GMVs). In contrast, higher positive urgency was correlated with smaller GMVs in many of the same regions. The dimensional impulsivity traits also involved distinct volumetric correlates, with, for instance, sensation seeking and positive urgency specifically implicating bilateral caudate head/mid-cingulate cortex and bilateral lateral orbitofrontal cortex/left precentral gyrus, respectively. Boys relative to girls scored higher in all impulsivity dimensions. Girls relative to boys showed significantly stronger positive and negative correlations between sensation seeking and insula, putamen, and inferior frontal gyrus (IFG) GMVs and between positive urgency and cingulate cortex, insula, and IFG GMVs, respectively. With a subsample of twins, the dimensional impulsivity traits were weakly to moderately heritable in both girls and boys, and the GMV correlates were highly heritable in girls and boys combined. These findings collectively suggest shared and nonshared as well as sex differences in the cerebral volumetric bases of dimensional impulsivity traits and may facilitate research of externalizing psychopathology in children.

What Happens if the Brain Goes Elsewhere? Reflections on Head Transplantation and Personal Embodiment

Brain transplants have long been no more than the subject of science fiction and engaging thought experiments. That is no longer true. Neuroscientists have announced their intention to transplant the head of a volunteer onto a donated body. Response has been decidedly mixed. How should we think about the moral permissibility of head transplants? Is it a life-saving/life-enhancing opportunity that appropriately expands the boundaries of medical practice? Or, is it a bioethical morass that ought not to be attempted? For the purposes of this paper, I set aside questions regarding the surgical operation's technological plausibility so as to focus on very basic questions regarding personal identity and the morality of head transplantation. The analysis begins with an exploration of the embodiment of persons. It considers whether persons can be conceptually distinguished from all parts of their body, even if they cannot be physically separated from some parts without loss of personhood. It argues that in most cases replacing body parts with reasonably similar parts will not destroy the conditions for sustaining personhood. However, as I explore, the phenomenology of personhood is such that some physical changes may prove to be too significant to maintain personal identity successfully over time. Given such complexity and the significance of the costs involved, the moral permissibility of head transplantation likely depends on recognizing that persons may give permission to collaborate in common activities, including projects with which others deeply disagree, provided that they only utilize the services and resources of free and consenting others.

Well-Being in Highly Hypnotizable Persons

Both hypnotizability and well-being are relevant to health. This study aimed to investigate whether high hypnotizability was positively associated with well-being and whether the latter was related to the activity of the behavioral inhibition/approach system (BIS/BAS). ANOVA revealed significantly higher scores on the General Well-Being Index (PGWBI) in highly hypnotizable (highs, n = 31) compared with low hypnotizable participants (lows, n = 53), with medium hypnotizable participants (mediums, n = 41) exhibiting intermediate values. This finding was discussed in relation to other hypnotizability-related traits, such as morpho-functional brain characteristics, equivalence between imagery and perception, and interoceptive sensitivity. A secondary finding was a nonsignificant gender difference in scores on the PGWBI. The highs' higher well-being could be considered a favorable prognostic factor for physical and mental health.

The link between the brain volume derived index and the determinants of social performance

Motivation, defined as the energizing of behavior in pursuit of a goal, is a fundamental element of our interaction with the world and with each other. Furthermore, as it is known that cooperation leads to higher levels of performance than do individual conditions, empathic concern is also crucial to all forms of helping relationships. A growing number of studies indicate that motivation and empathy are associated not only with organizational performance and study achievements, but also with the human brain. However, to date, no definite neuroimaging-derived measures are available to measure motivation and empathy objectively. The current research evaluated the association of motivation and empathy with the whole brain using the gray-matter brain healthcare quotient (GM-BHQ), an MRI-based quotient. Participants were 47 healthy adults. All subjects underwent structural T1-weighted imaging. Motivation levels were evaluated using four motivation scales: Behavioral Activation System (BAS), Self-Monitoring Scale (SMS), Self-Control Scale (SCS), and Behavioral Inhibition System (BIS). Interaction levels, including empathic concern, were evaluated using four subscales of the Interpersonal Reactivity Index (IRI). It was found that the GM-BHQ was most significantly sensitive to the BAS scale (p = 0.002). Furthermore, the GM-BHQ was moderately sensitive to the SMS (p = 0.028) and subscales of the IRI (p = 0.044 for Fantasy and p = 0.036 for Empathic Concern). However, no significant association was found between the GM-BHQ and other variables (BIS and SCS). These results suggest that the GM-BHQ might reflect motivation and empathic concern.

Sex Differences in the Behavioral Inhibition System and Ventromedial Prefrontal Cortex Connectivity

The reinforcement sensitivity theory proposes brain–behavioral systems that underlie individual differences in sensitivity to punishment and reward. Such trait sensitivity is assessed using the behavioral inhibition/activation system (BIS/BAS) scales. Recent studies have reported sex-linked neuroanatomical correlates of the BIS/BAS, especially in the regions belonging to the valuation and salience networks that are associated with the representation of subjective value (SV), whereas less effort has been focused on investigating the neurofunctional aspects associated with sex differences in the BIS/BAS. We tested whether functional connectivity (FC) of the regions associated with the representation of SV mediates the relationship between sex and BIS sensitivity in healthy young adults by using resting-state functional magnetic resonance imaging data and self-reported BIS/BAS measures. Compared with males, females had heightened BIS sensitivity and increased FC between the ventromedial prefrontal cortex (vmPFC) seed and posterior parietal areas; this FC mediated the impact of sex on BIS sensitivity. Given that the observed vmPFC FC maps are considered part of the default-mode network, which is involved in ruminative processes, and that the BIS is associated with rumination and negative affect, our results may have implications for psychiatric disorders such as depression and anxiety, both of which have high incidence in females.

Incongruence effects in cross-modal emotional processing in autistic traits: An fMRI study

In everyday life, emotional information is often conveyed by both the face and the voice. Consequently, information presented by one source can alter the way in which information from the other source is perceived, leading to emotional incongruence. Here, we used functional magnetic resonance imaging (fMRI) to examine neutral correlates of two different types of emotional incongruence in audiovisual processing, namely incongruence of emotion-valence and incongruence of emotion-presence. Participants were in two groups, one group with a low Autism Quotient score (LAQ) and one with a high score (HAQ). Each participant experienced emotional (happy, fearful) or neutral faces or voices while concurrently being exposed to emotional (happy, fearful) or neutral voices or faces. They were instructed to attend to either the visual or auditory track. The incongruence effect of emotion-valence was characterized by activation in a wide range of brain regions in both hemispheres involving the inferior frontal gyrus, cuneus, superior temporal gyrus, and middle frontal gyrus. The incongruence effect of emotion-presence was characterized by activation in a set of temporal and occipital regions in both hemispheres, including the middle occipital gyrus, middle temporal gyrus and inferior temporal gyrus. In addition, the present study identified greater recruitment of the right inferior parietal lobule in perceiving audio-visual emotional expressions in HAQ individuals, as compared to the LAQ individuals. Depending on face or voice-to-be attended, different patterns of emotional incongruence were found between the two groups. Specifically, the HAQ group tend to show more incidental processing to visual information whilst the LAQ group tend to show more incidental processing to auditory information during the crossmodal emotional incongruence decoding. These differences might be attributed to different attentional demands and different processing strategies between the two groups.

Regional gray matter volume associated with exercise dependence: A voxel-based morphometry study

Although regular physical exercise has multiple positive benefits for the general population, excessive exercise may lead to exercise dependence (EXD), which is harmful to one's physical and mental health. Increasing evidence suggests that stress is a potential risk factor for the onset and development of EXD. However, little is known about the neural substrates of EXD and the underlying neuropsychological mechanism by which stress affects EXD. Herein, we investigate these issues in 86 individuals who exercise regularly by estimating their cortical gray matter volume (GMV) utilizing a voxel‐based morphometry method based on structural magnetic resonance imaging. Whole‐brain correlation analyses and prediction analyses showed negative relationships between EXD and GMV of the right orbitofrontal cortex (OFC), left subgenual cingulate gyrus (sgCG), and left inferior parietal lobe (IPL). Furthermore, mediation analyses found that the GMV of the right OFC was an important mediator between stress and EXD. Importantly, these results remained significant even when adjusting for sex, age, body mass index, family socioeconomic status, general intelligence and total intracranial volume, as well as depression and anxiety. Collectively, the results of the present study provide crucial evidence of the neuroanatomical basis of EXD and reveal a potential neuropsychological pathway in predicting EXD in which GMV mediates the relationship between stress and EXD.

Association between Hippocampal Volume and Working Memory in 10,000+ 9-10-Year-Old Children: Sex Differences

AIM

This study tested sex differences in the association between hippocampal volume and working memory of a national sample of 9-10-year-old children in the US. As the hippocampus is functionally lateralized (especially in task-related activities), we explored the results for the right and the left hippocampus.

METHODS

This is a cross-sectional study using the Adolescent Brain Cognitive Development (ABCD) Study data. This analysis included baseline ABCD data (n = 10,093) of children between ages 9 and 10 years. The predictor variable was right and left hippocampal volume measured by structural magnetic resonance imaging (sMRI). The primary outcome, list sorting working memory, was measured using the NIH toolbox measure. Sex was the moderator. Age, race, ethnicity, household income, parental education, and family structure were the covariates.

RESULTS

In the overall sample, larger right (b = 0.0013; p < 0.001) and left (b = 0.0013; p < 0.001) hippocampal volumes were associated with higher children's working memory. Sex had statistically significant interactions with the right (b = -0.0018; p = 0.001) and left (b = -0.0012; p = 0.022) hippocampal volumes on children's working memory. These interactions indicated stronger positive associations between right and left hippocampal volume and working memory for females compared to males.

CONCLUSION

While right and left hippocampal volumes are determinants of children's list sorting working memory, these effects seem to be more salient for female than male children. Research is needed on the role of socialization, sex hormones, and brain functional connectivity as potential mechanisms that may explain the observed sex differences in the role of hippocampal volume as a correlate of working memory.

Gender-related differences in frontal-parietal modular segregation and altered effective connectivity in internet gaming disorder

BACKGROUND

Although previous studies have revealed gender-related differences in executive function in internet gaming disorder (IGD), neural mechanisms underlying these processes remain unclear, especially in terms of brain networks.

METHODS

Resting-state fMRI data were collected from 78 subjects with IGD (39 males, 20.8 ± 2.16 years old) and 72 with recreational game use (RGU) (39 males, 21.5 ± 2.56 years old). By utilizing graph theory, we calculated participation coefficients among brain network modules for all participants and analyzed the diagnostic-group-by-gender interactions. We further explored possible causal relationships between networks through spectral dynamic causal modeling (spDCM) to assess differences in between-network connections.

RESULTS

Compared to males with RGU, males with IGD demonstrated reduced modular segregation of the frontal-parietal network (FPN). Male IGD subjects also showed increased connections between the FPN and cingulo-opercular network (CON); however, these differences were not found in female subjects. Further spDCM analysis indicated that the causal influence from CON to FPN in male IGD subjects was enhanced relative to that of RGU males, while this influence was relatively reduced in females with IGD.

CONCLUSIONS

These results suggest poor modular segmentation of the FPN and abnormal FPN/CON connections in males with IGD, suggesting a mechanism for male vulnerability to IGD. An increased "bottom-up" effect from the CON to FPN in male IGD subjects could reflect dysfunction between the brain networks. Different mechanisms may underlie in IGD, suggesting that different interventions may be optimal in males and females with IGD.

Influence of ovarian hormones on value-based decision-making systems: Contribution to sexual dimorphisms in mental disorders

Women and men exhibit differences in behavior when making value-based decisions. Various hypotheses have been proposed to explain these findings, stressing differences in functional lateralization of the brain, functional activation, neurotransmitter involvement and more recently, sex hormones. While a significant interaction of neurotransmitter systems and sex hormones has been shown for both sexes, decision-making in women might be particularly affected by variations of ovarian hormones. In this review we have gathered information from animal and human studies on how ovarian hormones affect decision-making processes in females by interacting with neurotransmitter systems at functionally relevant brain locations and thus modify the computation of decision aspects. We also review previous findings on impaired decision-making in animals and clinical populations with substance use disorder and depression, emphasizing how little we know about the role of ovarian hormones in aberrant decision-making.

Gray matter volumetric correlates of behavioral activation and inhibition system traits in children: An exploratory voxel-based morphometry study of the ABCD project data

Approach and avoidance represent two fundamental behavioral traits that develop early in life. Previous studies have examined the neural correlates of approach and avoidance traits in adults and adolescents. Here, using the data set of the Adolescent Brain Cognition Development project, we investigated the structural cerebral bases of behavioral activation system (BAS) and behavioral inhibition system (BIS) in children. We employed voxel-based morphometry to examine how gray matter volumes (GMV) related specifically to BAS and BIS traits in 11,542 children (5491 girls, age 9-10 years) with 648 and 2697 identified as monozygotic twins (MZ) and dizygotic twins/siblings (DZ), respectively. After accounting for the BIS score, higher BAS scores (residuals) were positively correlated with the GMV of the ventral striatum (VS), and the correlation was stronger in MZ than in DZ and unrelated children, with a heritability (h²) of 0.8463. Higher BAS scores were negatively correlated with the GMV of bilateral visual, lateral orbitofrontal, temporal, and inferior frontal cortex, as well as the precuneus. Higher BIS (after accounting for BAS) scores were negatively correlated with the GMVs of the ventral caudate and bilateral putamen/pallidum, hypothalamus, and right anterior insula, and the correlation was stronger in MZ than in DZ and unrelated children, with a heritability of 0.8848. A cluster in the VS showed positive and negative correlation with the BAS and BIS scores, respectively. These findings suggest shared and distinct cerebral volumetric bases of the BAS and BIS traits in children. Whereas both traits have a strong genetic basis, the BAS relative to BIS appears to be more amenable to environmental influences. These findings add to the literature of developmental neuroscience and may help identify genetic risk factors of externalizing and internalizing psychopathology.

Sex differences in resting-state cerebral activity alterations in internet gaming disorder

Although evidence has shown that the prevalence rates of Internet gaming disorder (IGD) differ between males and females, few studies have examined whether such sex differences extend to brain function. This study aimed to explore the sex differences in resting-state cerebral activity alterations in IGD. Thirty male participants with IGD (IGDm), 23 female participants with IGD (IGDf), and 30 male and 22 female age-matched healthy controls (HC) underwent resting-state functional MRI. Maps of the amplitude of low-frequency fluctuation (ALFF) and functional connectivity (FC) were constructed. A two-factor ANCOVA model was performed, with sex and diagnosis as the between-subject factors. Then, post hoc pair-wise comparisons were performed using two-sample t-tests within the interaction masks. The Barratt Impulsiveness Scale-11 (BIS-11) was used to assess the behavioral inhibition function. We found that the ALFF values in the orbital part of the left superior frontal gyrus (SFG) were lower in IGDm than in HCm, which were negatively correlated with BIS-11 scores. IGDm also demonstrated lower connectivity between the orbital part of the left SFG and the posterior cingulate cortex (PCC), the right angular gyrus, and the right dorsolateral prefrontal cortex than HCm. Furthermore, IGDm had lower seed connectivity between the orbital part of the left SFG and the PCC than ICDf. Our findings suggest that (1) the altered ALFF values in the orbital part of the left SFG represent a clinically relevant biomarker for the behavioral inhibition function of IGDm; (2) IGD may interact with sex-specific patterns of FC in male and female subjects.

Sex Differences in the Association between Cortical Thickness and Children's Behavioral Inhibition

AIM

To investigate sex differences in the association between cortical thickness and behavioral inhibition of 9-10 years old American children.

MATERIALS AND METHODS

This cross-sectional investigation used data from the Adolescent Brain Cognitive Development (ABCD) study. Baseline ABCD data of 10249 American children between ages 9 and 10 were analyzed. The independent variable was cortical thickness measured by structural brain magnetic resonance imaging (sMRI). The primary outcome, behavioral inhibition, was measured based on the behavioral inhibition system (BIS), and behavioral approach system (BAS). Sex was the moderator. Age, race, ethnicity, socioeconomic status indicators, and intracranial volume were covariates.

RESULTS

In the overall sample, high cortical thickness was not associated with behavioral inhibition in children. Sex showed a statistically significant interaction with cortical thickness's effect on children's behavioral inhibition, net of all confounders. The interaction indicated a statistically stronger positive effect of high cortical thickness on male behavioral inhibition compared to female children.

CONCLUSION

Cortical thickness is a determinant of behavioral inhibition for male but not female American children. Male but not female children show better behavioral inhabitation at higher levels of cortical thickness.

Association between fatigue, motivational measures (BIS/BAS) and semi-structured psychosocial interview in hemodialytic treatment

Background

Nowadays there is a growing interest in exploring causes of fatigue symptoms and the possible linked aspects in patients with Chronic Kidney Disease (CKD) receiving hemodialysis (HD) treatment. Inflammatory processes were demonstrated to influence motivational systems functioning in chronic conditions. However, there is a lack of connection between quantitative motivational systems measure and patients self-report motivational and fatigue issue. Thus, the aim of this study was to identify an association between HD patients reward mechanisms, fatigue severity and psychosocial variables emerging from semi-structured interviews.

Methods

Interviews were held for a sample of ninety-four patients (54 males, 40 females; M_age = 62.98 ± 17.94; dialytic mean age in months = 76.55 ± 84.89) receiving chronic HD treatment and consequently analyzed by means of quantitative and qualitative analysis. Behavioral motivation systems reflecting inhibition/approach tendency to rewards were measured by Behavioral Inhibition/Activation System (BIS/BAS) scale and the fatigue severity experienced by HD patients was measured with the Fatigue Severity Scale. Scale results were correlated to psychosocial variables and topics derived from the semi-structured interviews.

Results

Findings highlight the presence of two effects: one related to the Behavioral Activation System (BAS) as a protective factor against the HD treatment pervasive consequences; the other one deals with the self-reported levels of fatigue that seemed to significantly interfere with patients’ daily life, as a function of gender.

Conclusions

Such results encourage the use of a mixed method approach to understand the complexity of the subjective experience of patients’ facing chronic disease and treatments.

Sex-Specific Relationship of Childhood Adversity With Gray Matter Volume and Temperament

Background: To date, many studies have attempted to show a relationship between potentially harmful experiences in childhood and gray matter volume (GMV) in specific brain areas. These studies managed to identify several affected regions, yet most of them neglected the influence of sex or the occurrence of mental health problems. Furthermore, little is known about mechanisms linking childhood adversity (CA) and temperamental traits as plausible endophenotypes of psychopathology. Objective: The present study addresses these two issues by trying to identify sex-specific relationships between CA and brain volumes as well as to show the role of the latter in predicting temperament scores. Method: Forty-eight people (23 women) without anxiety or affective disorders participated in this study. CA was measured using the Childhood Questionnaire (CQ) and temperament was measured with the use of the behavioral inhibition system-behavioral activation system (BIS-BAS) Scales. Whole-brain MR imaging was performed to identify GMV differences. Results: In women, we identified negative relationships between CA and GMV in the left inferior parietal lobule (IPL), right cerebellum, and right precentral gyrus. In men, we found a negative correlation between CA and GMV in the right fusiform gyrus. We also identified sex-specific relationships between CA and temperament traits. Conclusions: The results of our study suggest a sex-specific pattern in the relationship between early adverse experiences and brain structure. The results can also help explain the role that temperament plays in the relationship between CA and the risk of psychopathology.

Sex differences and personality in the modulation of the acoustic startle reflex

The modulation of the eyeblink component of the acoustic startle reflex (ASR) has been used to study human motivation, attention, and emotion towards affective stimuli of different valence. However, sex and individual differences in personality have been rather overlooked concerning the change in the ASR to brief affective sequences. In this study, we aimed to evaluate sex differences in the ASR, together with the influence of sensitivity to punishment (SP) and sensitivity to reward (SR) in the affective modulation of the ASR to pleasant and unpleasant pictures. We addressed this topic with a latent curve model (LCM) representing the change in the ASR of an extensive group of men (n = 166) and women (n = 109). There was a significant habituation of the ASR to the pleasant pictures, and a significant sensitization of the ASR to the unpleasant pictures. Both effects were higher and more variable for women than for men. There were in addition interactive and quadratic effects of SP and SR on the ASR to the pleasant and unpleasant pictures. Men and women with extreme scores in SP, and women with low scores in SR habituated faster to the pleasant stimuli. For men scoring low in SP, higher scores in SR related with an attenuated initial ASR to the unpleasant stimuli. Women with extreme scores in SP had a higher initial ASR to the unpleasant stimuli. There were remarkable asymmetries between men and women concerning personality effects on the change in the ASR to affective stimuli.

BAS-drive trait modulates dorsomedial striatum activity during reward response-outcome associations

According to the Reinforcement Sensitivity Theory, behavioral studies have found that individuals with stronger reward sensitivity easily detect cues of reward and establish faster associations between instrumental responses and reward. Neuroimaging studies have shown that processing anticipatory cues of reward is accompanied by stronger ventral striatum activity in individuals with stronger reward sensitivity. Even though establishing response-outcome contingencies has been consistently associated with dorsal striatum, individual differences in this process are poorly understood. Here, we aimed to study the relation between reward sensitivity and brain activity while processing response-reward contingencies. Forty-five participants completed the BIS/BAS questionnaire and performed a gambling task paradigm in which they received monetary rewards or punishments. Overall, our task replicated previous results that have related processing high reward outcomes with activation of striatum and medial frontal areas, whereas processing high punishment outcomes was associated with stronger activity in insula and middle cingulate. As expected, the individual differences in the activity of dorsomedial striatum correlated positively with BAS-Drive. Our results agree with previous studies that have related the dorsomedial striatum with instrumental performance, and suggest that the individual differences in this area may form part of the neural substrate responsible for modulating instrumental conditioning by reward sensitivity.

Neural determinants of human goal-directed vs. habitual action control and their relation to trait motivation

Instrumental learning is mediated by goal-directed and habit systems in the brain. While rodent studies implicate distinct prefrontal/striatal regions in goal-directed and habit learning, neural systems underpinning these two processes in humans remain poorly understood. Here, using a validated discrimination learning task that distinguishes goal-directed learning from habit learning in 72 subjects in fMRI, we investigated the corticostriatal correlates of goal-directed learning and tested whether brain activation during learning is associated with trait motivation and behavioral performance in the post-learning test phase. Participants showed enhanced activation in medial prefrontal and posterior cingulate cortices during goal-directed action selection in the training phase, whereas habitual action selection activated bilateral insula, bilateral dorsal caudate and left precentral gyrus. In addition, early phase of learning was associated with increased activation in the frontoparietal control network and dorsal striatum, whereas default mode regions depicted increased activation in the late phase. Finally, avoidance motivation scores measured by Behavioral Inhibition/Activation System (BIS/BAS) correlated with accuracy during goal-directed learning and showed a nominally significant correlation with activation in dorsomedial prefrontal cortex during goal-directed acquisition of stimuli. These findings reveal the temporal dynamics of instrumental behavior and suggest that avoidance motivation predicts performance and brain activity during goal-directed learning.

Biopsychological structure of Yin-Yang using Cloninger's Temperament model and Carver and White's BIS/BAS scale

Introduction. The purpose of this study was to examine the psychological structure of Yin-Yang based on the Sasang Personality Questionnaire (SPQ) in relation to Carver and White’s Behavior Inhibition/Behavior Activation System (BIS/BAS) Scale and Cloninger’s temperament model of the West.

Methods. A total of 188 university students were classified as high (30%), middle (40%), and low (30%) groups based on their SPQ score and their differences in Cloninger’s temperaments and BIS/BAS subscales were analyzed using analysis of covariance after controlling the sex. Correlation among SPQ, Cloninger’s four temperaments and BIS/BAS subscales was also examined.

Results. Significant differences in BAS (F = 11.703, p < .001), Novelty-Seeking (F = 4.945, p < .01), and Harm-Avoidance (F = 10.912, p < .001) were observed between high and low SPQ score groups after controlling for sex. The SPQ showed significant correlation with BAS (r = 0.303), Novelty-Seeking (r = 0.225), and Harm-Avoidance (r = − 0.273). However, BIS showed no significant differences between SPQ groups, and did not show correlation with the SPQ.

Discussion. The current study demonstrated that Yin-Yang has similarities with and disparities from the Western tradition and may be examined with objective instruments. We showed that the emotionality of the East which is defined as mobility of emotion, not emotional instability as traditionally defined in Western theories, is pivotal for understanding the nature of emotion in the East. Suggestions are made for cross-cultural psychobiological study of the East and West.

Study on the Difference of BIS/BAS Scale between Sasang Types

Introduction. The purpose of this study was to examine the differences in temperament between So-Yang (SY) and So-Eum (SE) Sasang types using Behavioral Inhibition System/Behavioral Activation System (BIS/BAS) scale to elucidate the biopsychological mechanism underlying the Sasang typology, a traditional Korean personalized medicine. Methods. 248 university students were categorized into three Sasang types, and series of t-tests were conducted, separately for male and female participants, to examine the difference of Behavioral Inhibition System (BIS), Behavioral Activation System (BAS), BAS-Drive (BAS-D), BAS-Fun Seeking (BAS-FS), and BAS-Reward Responsiveness (BAS-RR) scores between SY and SE Sasang types. Results. There were significant differences between Sasang types in the BIS/BAS subscales with consideration of gender. In male participants, BAS-total score of SY type (39.75 ± 4.56) was significantly (t = 2.462, p = 0.016) higher than that of SE type (36.68 ± 4.97). On the other hand, in female participants, BIS score of SY type (20.10 ± 4.01) was significantly (t = -2.097, p = 0.039) lower than that of SE type (21.83 ± 3.91). Discussion. The current study suggested relationship between Sasang typology and Behavior Inhibition and Activation Systems and showed significant differences in BIS/BAS scale between SY and SE Sasang types. Further studies on biological base of Sasang typology are needed.

Barratt Impulsivity and Neural Regulation of Physiological Arousal

Background

Theories of personality have posited an increased arousal response to external stimulation in impulsive individuals. However, there is a dearth of studies addressing the neural basis of this association.

Methods

We recorded skin conductance in 26 individuals who were assessed with Barratt Impulsivity Scale (BIS-11) and performed a stop signal task during functional magnetic resonance imaging. Imaging data were processed and modeled with Statistical Parametric Mapping. We used linear regressions to examine correlations between impulsivity and skin conductance response (SCR) to salient events, identify the neural substrates of arousal regulation, and examine the relationship between the regulatory mechanism and impulsivity.

Results

Across subjects, higher impulsivity is associated with greater SCR to stop trials. Activity of the ventromedial prefrontal cortex (vmPFC) negatively correlated to and Granger caused skin conductance time course. Furthermore, higher impulsivity is associated with a lesser strength of Granger causality of vmPFC activity on skin conductance, consistent with diminished control of physiological arousal to external stimulation. When men (n = 14) and women (n = 12) were examined separately, however, there was evidence suggesting association between impulsivity and vmPFC regulation of arousal only in women.

Conclusions

Together, these findings confirmed the link between Barratt impulsivity and heightened arousal to salient stimuli in both genders and suggested the neural bases of altered regulation of arousal in impulsive women. More research is needed to explore the neural processes of arousal regulation in impulsive individuals and in clinical conditions that implicate poor impulse control.